SOUNDS OF seaplanes

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greetings

i don't know a lot about aviation but sure someone here does

so the question is

why do seaplane motors sound heavier? and more distinctive
than their land based counterparts?

live near water and i can tell by the sound if it has floats or wheels

must be a reason for this

thanks

bill

[Mike O'Malley]

> wrote in message
...
> greetings
>
> i don't know a lot about aviation but sure someone here does
>
> so the question is
>
> why do seaplane motors sound heavier? and more distinctive
> than their land based counterparts?
>
> live near water and i can tell by the sound if it has floats or wheels
>
> must be a reason for this
>

Generally, seaplanes will be fitted with larger diameter propellers than
their land counterparts. This translates to higher prop tip speeds, some
approaching supersonic. Higher speed at the tips relates to more noise.

--
Mike O'Malley

[Vern]

"Mike O'Malley" > wrote in
:


> Generally, seaplanes will be fitted with larger diameter propellers than
> their land counterparts. This translates to higher prop tip speeds, some
> approaching supersonic. Higher speed at the tips relates to more noise.
>
> --
> Mike O'Malley
>



Is there a trade-off somewhere else in the perfomance envelope that makes
the larger prop less desireable on the land based versions?

[Scott Skylane]

Vern wrote:
> "Mike O'Malley" > wrote in
> :
>
>
>
>>Generally, seaplanes will be fitted with larger diameter propellers than
>>their land counterparts. This translates to higher prop tip speeds, some
>>approaching supersonic. Higher speed at the tips relates to more noise.
>>
>>--
>>Mike O'Malley
>>
>
>
>
>
> Is there a trade-off somewhere else in the perfomance envelope that makes
> the larger prop less desireable on the land based versions?

Yes, ground clearance (esp. with deflated nose strut and/or tire).

[Vern]

Scott Skylane > wrote in
:

>>
>> Is there a trade-off somewhere else in the perfomance envelope that
>> makes the larger prop less desireable on the land based versions?
>
> Yes, ground clearance (esp. with deflated nose strut and/or tire).
>
>



Hee hee...why is it always the obvious one's that stump me?!

[QDurham]

> Yes, ground clearance (esp. with deflated nose strut and/or tire).
>>
Hee hee...why is it always the obvious one's that stump me?!
>

Perhaps because this isn't necessarily correct. Prop blade impact with water
is every bit as damaging to the prop as asphalt -- if not worse. I bet
seaplanes sound different from landplanes (if indeed they do) because of the
sound reflectivity of water vs asphalt/concrete/whatever.

Quent

[Mike O'Malley]

"Vern" > wrote in message
ble.rogers.com...
> Is there a trade-off somewhere else in the perfomance envelope that makes
> the larger prop less desireable on the land based versions?

This is just an assumption, but my educated guess would be that a larger
diameter propeller will create more static thrust, at the expense of cruise
seed. This is my experience flying a a 150hp Super Cub that went from a
standard 74" climb prop to an 84" seaplane prop (made it easier to hand prop
as well) The sea plane has more drag to overcome because of the floats in
the water versus wheels on the ground. Seaplanes have already sacrificed
speed for utility, what's a little more.

FWIW, some land planes DO have larger seaplane props, mainly aircraft that
need better shortfield performance. Bush planes, and banner tow aircraft
come to mind. Cruise speed is less of an issue, second to short field
performance, or extra thrust. The Super Cub lost about 5 knots off the top
end in cruise, but required 150 rpm less to pull the same banner, and had a
much shorter prop.

[Vern]

(QDurham) wrote in
:

>> Yes, ground clearance (esp. with deflated nose strut and/or tire).
>>>
> Hee hee...why is it always the obvious one's that stump me?!
>>
>
> Perhaps because this isn't necessarily correct. Prop blade impact
> with water is every bit as damaging to the prop as asphalt -- if not
> worse. I bet seaplanes sound different from landplanes (if indeed
> they do) because of the sound reflectivity of water vs
> asphalt/concrete/whatever.
>
> Quent
>
>
>



Yeah but think about it...ground to pro tip clearance when an aircraft is
on it's gear will be much less than when it is on floats thus allowing a
larger prop. If an aircraft has nosed over in the water enough for the
tips to strike then the LEAST of your worries is what will happen to your
prop!!

[Vern]

"Mike O'Malley" > wrote in
:

> This is just an assumption, but my educated guess would be that a
> larger diameter propeller will create more static thrust, at the
> expense of cruise seed. This is my experience flying a a 150hp Super
> Cub that went from a standard 74" climb prop to an 84" seaplane prop
> (made it easier to hand prop as well) The sea plane has more drag to
> overcome because of the floats in the water versus wheels on the
> ground. Seaplanes have already sacrificed speed for utility, what's a
> little more.
>
> FWIW, some land planes DO have larger seaplane props, mainly aircraft
> that need better shortfield performance. Bush planes, and banner tow
> aircraft come to mind. Cruise speed is less of an issue, second to
> short field performance, or extra thrust. The Super Cub lost about 5
> knots off the top end in cruise, but required 150 rpm less to pull the
> same banner, and had a much shorter prop.
>


Very good points...thanks for enlightening. I've only ever flown the land
based buggers myself.

[PJ Hunt]

Because 'real' seaplane motors are round. :)

a beaver pilot.

===============================

"Mike O'Malley" > wrote in message

> > why do seaplane motors sound heavier? and more distinctive
> > than their land based counterparts?
> Mike O'Malley